Flavor violating leptonic decays of τ and μ leptons in the Standard Model with massive neutrinos Hernández Tomé, G. López Castro, Gabriel Roig, P. We have revisited the computations of the flavor violating leptonic decays of the τ and μ leptons into three lighter charged leptons in the Standard Model with massive neutrinos. We were driven by a claimed unnaturally large branching ratio predicted for the τ − → μ − l + l − (l = μ, e) decays (Pham, Eur Phys J C 8:513 1999), which was at odds with the corresponding predictions for the μ − → e−e−e+ processes (Petcov, Sov J Nucl Phys 25:340 1977). In contrast with the prediction in [17], our results are strongly suppressed and in good agreement with the approximationmade in Ref. [15], where masses and momenta of the external particles were neglected in order to deal with the loop integrals. However -as a result of keeping external momenta and masses in the computation of the dominant penguin and box diagrams- we even find slightly smaller branching fractions. Therefore, we confirm that any future observation of such processes would be an unambiguous manifestation of new physics beyond the Standard Model. 2020-02-04T11:15:57Z 2020-02-04T11:15:57Z 2019 info:eu-repo/semantics/article Hernández-Tomé, G., Castro, G. L., & Roig, P. (2019). Flavor violating leptonic decays of τ and μ leptons in the Standard Model with massive neutrinos. The European Physical Journal C, 79(1), 84. http://hdl.handle.net/10481/59405 10.1140/epjc/s10052-019-6563-4 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España Springer Nature